Dynamic anchors

What is the reasoning behind using static rope for natural anchors as opposed to dynamic rope?

Static rope doesn't stretch.  Say you used a dynamic rope to build a top rope anchor on a tree, the masterpoint would still extend over the edge of the cliff.  Any time a dynamic rope runs over the edge of a cliff it can be sawed through from weighting and unweighting the rope because it stretches back and forth.  

Static rope is also tougher stuff.

It's also cheaper -- which, given that it's safe, is probably its biggest selling point.

Say I have a length of dynamic rope that would work perfectly for anchors. Assuming it doesn’t run over any sharp edges, is there any reason I shouldn’t use it?

I’d prefer to use what I have rather than buying something else. 

Assuming it isn’t compromised, then your section of dynamic rope should be fine. Just wrap a towel or old shirt or some tubular webbing around the rope against any rough rock to keep the life longer.

Your question really should be, why isn't all climbing pro from quickdraws to alpine runners to cams using dynamic material instead of static dyneema/nylon?

Go for it. The bulk seems obnoxious, but it's safe.

I use clean nice sections of former dynamic ropes from time to time. Mostly for random rappel when the trees aren't close enough to the end of the cliff and dirtier setup, when I don't want to use good clean anchor material I intent to keep using for long. I don't mind leaving it there either, since it isn't much use for anything else at that point.

Process generally goes like this:

• 70m Outdoor lead rope
• ~60m outdoor backup lead rope or 2nd rope for multi pitches (depending on where/how sore spots/abrasion develops)
• 1 or 2 indoor lead rope (same)
• Bits of rope for anchors & random stuff

When you set your anchor, you'll have 2 strands or dynamic rope. That lessens any strech by a LOT. Also an anchor isn't that long - so some % of not very long means not a whole lot of stretching. Since I presume you'll top rope out of a dynamic rope, any anchor stretch is by far lost in the rope stretch itself...

Another example of when you may use dynamic rope as an anchor (which is also perfectly fine) is when doing multiple pitches & using the rope as anchor material. Quite common & useful is you don't have enough left (or forgot the anchor at the previous belay.....)

Long Ranger wrote: Your question really should be, why isn't all climbing pro from quickdraws to alpine runners to cams using dynamic material instead of static dyneema/nylon?

Haha nice

Thanks for the input. Frank and Chris K, that was my thinking. It’s an old gym rope that I won’t use for anything else now.